feat: authorize scoped symlink paths lexically

crates/fs-operation/src/glob.rs

@@ -3,7 +3,7 @@ use std::path::{Path, PathBuf};
 use globset::Glob;
 use ignore::WalkBuilder;
 
-use crate::{FsAccessPolicy, FsError, FsPath, GlobRequest, GlobResult, direct_symlink};
+use crate::{FsAccessPolicy, FsError, FsPath, GlobRequest, GlobResult};
 
 /// Execute a bounded glob entirely inside the provider process.
 pub fn run_glob(
@@ -18,21 +18,13 @@ pub fn run_glob(
     if !access.is_readable(base) {
         return Err(FsError::OutOfScope(PathBuf::from(request.path.as_str())));
     }
-    if let Some(info) = direct_symlink(base)
-        && info.target_exists
-        && info.resolved_path.is_dir()
-    {
-        return Err(FsError::SymlinkDirectoryNotTraversed {
-            tool: "Glob",
-            path: PathBuf::from(request.path.as_str()),
-            target: PathBuf::from("<provider-internal target>"),
-        });
-    }
     let matcher = Glob::new(&request.pattern)
         .map_err(|error| FsError::InvalidGlob(error.to_string()))?
         .compile_matcher();
     let mut matches = Vec::new();
-    for entry in WalkBuilder::new(base).hidden(false).build().flatten() {
+    let mut walker = WalkBuilder::new(base);
+    walker.hidden(false).follow_links(false);
+    for entry in walker.build().flatten() {
         let path = entry.path();
         if !path.is_file() || !access.is_readable(path) {
             continue;

crates/fs-operation/src/lib.rs

@@ -477,13 +477,14 @@ mod tests {
 
     #[cfg(unix)]
     #[test]
-    fn grep_keeps_direct_symlink_directory_and_broken_path_guards() {
+    fn grep_traverses_a_direct_symlink_directory_and_rejects_a_broken_path() {
         use std::os::unix::fs::symlink;
 
         let temp = tempfile::tempdir().unwrap();
         let root = temp.path().canonicalize().unwrap();
         let readable = RootAccess(root.clone());
         std::fs::create_dir(root.join("target-dir")).unwrap();
+        std::fs::write(root.join("target-dir/nested.rs"), "needle nested\n").unwrap();
         std::fs::write(root.join("target-file.rs"), "needle file\n").unwrap();
         symlink(root.join("target-file.rs"), root.join("file-link.rs")).unwrap();
         symlink(root.join("target-dir"), root.join("directory-link")).unwrap();
@@ -501,18 +502,35 @@ mod tests {
         assert_eq!(file_result.match_count, 1);
         assert!(file_result.output.starts_with("file-link.rs\n"));
 
-        let directory_error = run_grep(
+        let directory_result = run_grep(
             &root,
             root.join("directory-link"),
             request("directory-link"),
             &readable,
         )
-        .unwrap_err();
-        assert!(matches!(
-            directory_error,
-            FsError::SymlinkDirectoryNotTraversed { tool: "Grep", path, .. }
-                if path == root.join("directory-link")
-        ));
+        .unwrap();
+        assert_eq!(directory_result.match_count, 1);
+        assert!(
+            directory_result
+                .output
+                .starts_with("directory-link/nested.rs\n")
+        );
+
+        let glob_result = run_glob(
+            &root,
+            &root.join("directory-link"),
+            GlobRequest {
+                pattern: "**/*.rs".to_string(),
+                path: FsPath::new("directory-link").unwrap(),
+                limit: 10,
+            },
+            &readable,
+        )
+        .unwrap();
+        assert_eq!(
+            glob_result.paths,
+            vec![FsPath::new("directory-link/nested.rs").unwrap()]
+        );
 
         let broken_error = run_grep(
             &root,

crates/fs-operation/src/local.rs

@@ -45,7 +45,7 @@ pub fn run_read(
 ) -> Result<ReadResult, FsError> {
     let logical = request.path;
     let path = resolve(root, &logical)?;
-    let path = require_access(&path, &logical, access, false)?;
+    let path = require_access(&path, &logical, access, false, false)?;
     let metadata = fs::metadata(&path).map_err(|error| map_io(&logical, error))?;
     if metadata.is_dir() {
         return Err(FsError::IsDirectory(PathBuf::from(logical.as_str())));
@@ -99,7 +99,7 @@ pub fn run_write(
     let path = resolve(root, &logical)?;
     let created = !path.exists();
     if path.exists() {
-        let target = require_access(&path, &logical, access, true)?;
+        let target = require_access(&path, &logical, access, true, false)?;
         let metadata = fs::metadata(&target).map_err(|error| map_io(&logical, error))?;
         if metadata.is_dir() {
             return Err(FsError::IsDirectory(PathBuf::from(logical.as_str())));
@@ -117,7 +117,7 @@ pub fn run_write(
             FsError::InvalidArgument(format!("{} has no parent", logical.as_str()))
         })?;
         let parent_logical = logical_parent(&logical);
-        require_access(parent, &parent_logical, access, true)?;
+        require_access(parent, &parent_logical, access, true, true)?;
         atomic_write(&path, &request.content, &logical)?;
     }
     Ok(WriteResult {
@@ -133,7 +133,7 @@ pub fn run_edit(
 ) -> Result<EditResult, FsError> {
     let logical = request.path;
     let path = resolve(root, &logical)?;
-    let target = require_access(&path, &logical, access, true)?;
+    let target = require_access(&path, &logical, access, true, false)?;
     let bytes = fs::read(&target).map_err(|error| map_io(&logical, error))?;
     let actual_hash = hash_bytes(&bytes);
     if actual_hash != request.expected_hash {
@@ -173,7 +173,7 @@ pub fn run_list(
 ) -> Result<ListResult, FsError> {
     let logical = request.path;
     let path = resolve(root, &logical)?;
-    let path = require_access(&path, &logical, access, false)?;
+    let path = require_access(&path, &logical, access, false, true)?;
     let metadata = fs::metadata(&path).map_err(|error| map_io(&logical, error))?;
     if !metadata.is_dir() {
         return Err(FsError::NotDirectory(PathBuf::from(logical.as_str())));
@@ -247,6 +247,7 @@ fn require_access(
     logical: &FsPath,
     access: &dyn FsAccessPolicy,
     write: bool,
+    allow_symlink_directory: bool,
 ) -> Result<PathBuf, FsError> {
     if let Some(info) = direct_symlink(path) {
         if !info.target_exists {
@@ -257,9 +258,9 @@ fn require_access(
             });
         }
         let allowed = if write {
-            access.is_writable(&info.resolved_path)
+            access.is_writable(path)
         } else {
-            access.is_readable(&info.resolved_path)
+            access.is_readable(path)
         };
         if !allowed {
             return Err(FsError::SymlinkOutOfScope {
@@ -268,7 +269,7 @@ fn require_access(
                 required_permission: if write { "write" } else { "read" },
             });
         }
-        if write && info.resolved_path.is_dir() {
+        if !allow_symlink_directory && info.resolved_path.is_dir() {
             return Err(FsError::SymlinkTargetIsDirectory {
                 path: PathBuf::from(logical.as_str()),
                 target: PathBuf::from("<provider-internal target>"),

crates/fs-operation/src/search.rs

@@ -259,16 +259,6 @@ pub fn run_grep(
             base.display()
         )));
     }
-    if base_meta.is_dir()
-        && let Some(info) = symlink.as_ref()
-    {
-        return Err(FsError::SymlinkDirectoryNotTraversed {
-            tool: "Grep",
-            path: base.clone(),
-            target: info.resolved_path.clone(),
-        });
-    }
-
     let filter_base = if base_meta.is_file() { root } else { &base };
     let types = build_types(p.file_type.as_deref())?;
     let overrides = build_overrides(filter_base, p.glob.as_deref())?;